The present invention relates to a compact, collapsible keyboard.
In the prior art, various compact, folding QWERTY keyboards have been proposed for use with mobile telephones, electronic organizers, and portable computers. Collapsible keyboards that employ mechanical, depressible key switches are constrained in size reduction by the bulk of these switches. In U.S. Pat. No. 6,174,097, a standard sized QWERTY keyboard is folded on three parallel axes, collapsing four rigid subframes of the keyboard to offer folded dimensions measuring a quarter of its unfolded width. However, the thickness of the keyboard is quadrupled when folded, and its potential size reduction is limited by its exclusive use of mechanical, depressible key switches.
Furthermore, such keyboards, when unfolded, demand large surface areas upon which to rest. As portable computer sizes have decreased, computer users have been able to employ these devices in situations that do not offer substantial desk or tabletop space. However, the size of standard QWERTY keyboards, foldable or otherwise, precludes their use in many of these situations. In such situations, typist must resort to the use of substantially smaller keyboards that only allow typing with the thumbs, with individual fingers, or with a stylus.
In U.S. Pat. No. 6,262,717, the entire keyboard is comprised of capacitance-responsive surfaces. In this way, substantial size reduction is achieved; however, this purely capacitance-responsive keyboard does not allow the fingers to rest on home keys, and, therefore, does not allow the use of familiar QWERTY style finger movements.
U.S. Pat. No. 5,497,151 attempts to reduce keyboard size by tightly interspersing the keys traditionally operable by the fingers of a person's left hand with the keys traditionally operable by the person's right hand. This proposal affords some reduction in size but is designed for single-handed typing and does not allow standard two-handed QWERTY typing.
It would be advantageous to provide a more compact keyboard offering the option of using both hands in the familiar QWERTY mode of typing. The present invention in a preferred embodiment offers two-handed typing in approximate QWERTY mode, while reducing the dimensions of the keyboard both in its folded and unfolded states.